The presence of the tiny ring moon Daphnis is betrayed by the edge waves it creates in the Keeler gap.
The gap is a narrow lane, about 42 kilometers (26 miles) wide, in Saturn's outer A ring. Daphnis (7 kilometers, or 4.3 miles across) was discovered in Cassini spacecraft images at the same time that scientists spotted the edge waves. Researchers had suspected the presence of a moon in this gap after Pan was discovered in Voyager spacecraft images taken 25 years earlier.
This view looks toward the unilluminated side of the rings from about 54 degrees above the ringplane.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 17, 2007 at a distance of approximately 1.8 million kilometers (1.1 million miles) from Saturn. Image scale is 10 kilometers (6 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. The Cassini imaging team homepage is at http://ciclops.org.
Daphnis cruises through the Keeler Gap, raising edge waves in the ring material as it passes.
As is characteristic of waves raised by a moon on the edges of a very narrow gap like Keeler, the wave begins as a coherent form near Daphnis and becomes less so with increasing orbital distance from the moon.
Daphnis is 7 kilometers (4.3 miles) across.
This view looks upon the lit side of the rings from about 31 degrees below the ringplane.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 17, 2007 at a distance of approximately 768,000 kilometers (477,000 miles) from Daphnis. Image scale is 5 kilometers (3 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. The Cassini imaging team homepage is at http://ciclops.org.
This Cassini view features several interesting attributes that show how moons help shape the rings of Saturn.
The embedded moon Daphnis (7 kilometers, or 4.3 miles across) is seen in its narrow gap at lower right. The tiny moon is accompanied by its entourage of edge waves, visible as ripples in the gap's edges.
Right of center, the much broader Encke Gap displays its own edge waves, caused by Pan (26 kilometers, or 16 miles across at its widest point). Also seen are several faint ringlets that inhabit the gap along with Pan.
Just outside, or leftward, of the Encke Gap is a dark, rippling moiré pattern, which occurs when two separate patterns in the rings are superposed on each other but are oriented at different angles to each other. In this case, the moiré pattern is created by interference between wakes caused by a recent passage of Pan and a spiral density wave created by the moon Prometheus. (See PIA08824 for a closer view of a spiral density wave.)
This view looks toward the unilluminated side of the rings from about 4 degrees above the ringplane. The narrow F ring arcs through the scene from lower right toward left.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 4, 2008. The view was obtained at a distance of approximately 1.3 million kilometers (800,000 miles) from Saturn. Image scale is 8 kilometers (5 miles) per pixel in the radial, or outward from Saturn, direction.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/. The Cassini imaging team homepage is at http://ciclops.org.
Voir l'image PIA09881: Ring-Moon Connections sur le site de la NASA.